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Feb. 16, 1932. 1 M U 1,845,164

CALCULATING MACHINE Filed March 20, 1929 5 Sheets-Sheet 1 J h H.

ATTORNEYS V Feb. 16, 1932.

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CALCULATING MACHINE Filed March 20, 1929 5 Sheets-Sheet 3 INVENTO A fohn ijvaynus @(ZW'I Ma, YM

A/TTORNEYS Feb. 16, 1932. MAGNUS 1,845,164

CALCULATING MACHINE Filed March 20, 1929 5 Sheets-Sheet 5 INVENTOR i/oim H. Wggmzs $2; than? ATTORNEYS Patented Feb. 16, 1932 UNITED STATES PATENT .OFFICE' JOHN H. MAGNUS, OF DETROIT, MICHIGAN, ASSIGNOR T BURROUGHS ADDING MACHINE COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN CALCULATING MACHINE 7 Application filed March 20, 1929. Serial No. 348,510.

This invention relates to a calculating machine.

It relates particularly to a calculating machine of the type disclosed in my co-pending application, Serial No. 289,865, filed July 2,

1928, and it concerns an improvement on said machine for facilitating the use of the machine in performing subtraction and division.

The machine of said application is an automatic electric calculator having a plurality of banks of keys with an individual differential mechanism for each bank, each differential mechanism operating a register pinion. The machine is driven by a normally inactive electric motor. When a key in a bank is ,ential mechanism for that bank is connected to the motor. The motor then drives the difi'erential mechanism until it is arrested by the depressed key, whereupon it is automatically disconnected, the motor is stopped, and a the diiier'ential mechanism returned to normal. During this series of operations the register pinion of the bank in which the operations took place is advanced an amount corresponding to the key depressed. Subtraction is performed on this prior machine by a' process of complemental addition and division is accomplished by repeated subtraction. As is well understood in the art, it is necessary, after adding the complement of a subtrahend to a minuend, to add 9 in all columns of the machine to the left of the last column in which an amount key was desubtrahend. This sometimes makes it necessary to depress quite a number of 9 keys and, while an experienced operator may do this very quickly and reasonably easily, it takes a certain amount of time and it offers the possibility of error, both of which are factors to be eliminated, if possible. The present invention is directed to an improvement by means of which the necessary keys are automatically operated upon manipulation of a single member thereby speeding up the work and reducing the chance for error.

The object of the invention is to provide depressed the motor is started and the differpressed in entering the complement of the an improved calculating machine capable of performing subtraction in a rapid and easy manner.

Other objects and advantages of the in" vention will appear from the specification and drawings.

An embodiment of the invention is shown in the drawings in which: p

Figure 1 is a sectional side elevation of a calculating machine with certain of the parts omitted, the view showing how the invention is ppplied to the machine;

*igure 2 is a plan view showing the board of the calculating machine;

Figure 3 is a perspective of a portion of the front end of the calculating machine illustrating particularly the mechanism used in connection with subtraction operations;

Figure 4 is a perspective view of one of the irregular shaped arms used in the machine;

Figure 5 is an enlarged partial side eleve tion and section of the forward part of the calculating machine, illustrating the parts in normal position, the parts being those of a bank other than the units bank;

Figure 6 is a view similar to Fig. 5, showing the parts in the position they occupy when one of the column keys is depressed in connection with a subtraction operation;

Figure 7 is a perspective view of a portion of the mechanism for connecting the differential stop bars to the motor drive.

General construction The calculator is provided with a plurality of banks of depressible amount keys 10, there being nine keys in each bank and preferably nine banks though the number of banks may be varied. These keys are mounted in a keyboard 11 and each is urged upwardly by a spring 12. Each key has a lateral projection 13 adapted to bepositioned for engagement by shoulder stops 14 on an indexing bar 15.

There is an indexing bar 15 for each bank of keys and each bar is pivotally connected at its forward end to a pivoted toothed segment 16. Each segment meshes with a gear 18 which, through suitable connections, rotates one of the register pinions 19 that control indicating dials 20 visible through the opening 21 in the casing 22 of the machine.

The indexing bar and its associated parts- I ate the register.

constitute What may be termed a difierential mechanism, that is, a mechanism which 1s movable to difierential positions under the control of the amount keys in order to oper- The series of inions -19, of which there is one for each ban of keys, comprise a register associated with which is a transfer mechamotor having connections for rotating a shaft 31'carrying a series of toothed pinions 32 there being a pinion for each bank of the machine. When the motor is running the pinions are rotated counterclockwise as indicated by the arrow in Fig. 1. Pivoted loosely on the shaft 31 isa series of arms 33 there being an arm for each bank and each arm having a slot in its upper endinto which projects a stud 34 on the respective indexing bar 15 of its bank. Each arm is urged clockwise by a spring 35 which acts to return the arm and its corresponding indexing bar to normal after they have been moved forward and released as will be later described. I

The electric motor is normallyinactive, but, upon depression of any of the amount keys, its circuit is closed and it is started. .This is accomplished throughthe medium of a longitudinally movable bar 36 urged tothe left in Fig. 1 by a spring 37. There is one of these bars for each bank of keysand the upper side of each bar is provided with a plurality of cam' slots 38 with which the lower ends of the amount keys cooperate. When any of the amount keys is depressed, its lower end en g ges in one of the slots 38 and moves the bar 36 to the right in Fig. 1. The bar has a downwardly extending projection 39 positioned to engage a bail 40 that controls the I combined governor and switch41 for 'start ini the motor.

rom the description thusfar given will be apparent that, when one of the amount keys 10 is'fdepre'ssed, the bar 36 for that bank is moved to the right and the motor started. At thesame time the projection 13 on the stem of thedepressedkey moves down into the path of the appropriate stop shoulder 14 on the indexing bar 15s0' as to arrest the bar when it has been moved forward as will be presently described.

' When the bar 36 is moved to the right, as

viewed in Figs. 1 and 7, it is latched in motor-starting position by means of a latch 50- pivoted to the rear of the bar and' having a hooked nose 51 that engages'over a plate 52, there being alatch for each bar.

back to normal under the influence of its clockwise, the ledge 54 is moved rom under .34 on indexing bar'15 by means of the same engagement of one of-its shoulders 14 with rocks the member clockwise on its pivot 61 so as to be operated by the toothed segment,

I This prevents the bar from immediately moving spring when pressure on the ke is released. As the latch 50 moves rearwar a shoulder 52 on it engages a lug 52 on a pivoted yokeshaped latch 53 and swings th1s latch counterclockwise. The latch 53 has another arm carrying a ledge 54 that is normally positioned under the nose of a pawl 55 which, as illustrated in Figs. 1 and 7, is pivoted at 56 to the arm 33 and urged clockwise by a spring 57. As the latch 53 swin s counterthe nose of pawl 55 and when the pawl 55 is released, the spring 57 snaps it into engagement with the toothed pinion 32 of its bank. Since the pawl 55 is carried by the arm 33, 8 the result 1s that the arm is connected to the toothed pinion that is rotated by the. motor. When this connection occurs the arm 33 is swung forward in a counterclockwise direction carryin the indexing bar 15 with it. The connection beween the arm 33 and the indexing bar 15 isa positive one at the beginning of the movement owing t0.the fact that the arm 33 has an extension 58 that en--' gages a shoulder .59 on the bar 15. After movement has been started the arm 58 swings away from the shoulder 59 and the connection between the arm 33 and the indexing bar 15 becomes a yielding one, that is, the drive is through a member 60 pivoted at 61 to the arm 33 and urged in a counterclockwise direction into engagement with the stud spring 57 that is connected to the pawl 55.

The indexing-bar 15 moves forward until it is arrested in difi'erential positionby the the depressed amount key. When this occurs the'upper end of the arm 33 moves for ward slightly relative'to the bar 15 and this and swings the spring 57 across the center of pivot 56 so that the spring 57 then acts to rock the pawl 55 counterclockwise out of engagement with the toothed pinion 32. This disconnects the difierential mechanism from, the motor, drive and frees the indexing bar and the arm 33 so that they may be returned to normal by the spring- 35. The rocking of the member 6O clockwlse also acts to raise the latch, 50 to release the motor starting bar 36 and the latter is then returned to normal by its spring 37 and the motor'switch opens to stop the motor. .It will be understood that after theindexing bar 15 has been moved to differential position, the register mechanism is conditioned 16 upon the return of the indexing bar to normal. The mechanism for doing this has not been illustrated as it is well known, the same being disclosed in Horton Patents Nos. 1,016,501, 1,156,600 and the Gooch patent previously mentioned. I v

It will thus be understood that an electric calculator has been provided that is entirely automatic and which acts instantaneously upon the depression of an amount key to register the amount of said key in the registering mechanism. When a key in any bank is depressed, the differential mechanism for that bank is automatically connected to the motor drive and the motor is started. The differential mechanism is then driven forward until arrested by the depressed key whereupon it is automatically disconnected from the motor drive and the motor is stopped. The whole operation takes place instantaneously and without requiring any attention on the part of the operator except the depression of the amount keys.

Subtraction feature added to the 1, which then causes the register in that order to register 0 buta carry takes place and the 1 appears in the est order to the left so that it is necessary to d the banks to the left of u in all or 7 those actually used in entering the complement of the subtrahend. This operation is a familiar one in calculating machines.

'ls illustrated in Fig. 2, the amount keys provided with complemental numbers are slightly smaller than the regular 1 embers but which facilitate the use of the n achine' in subtraction. When an operator wis' es to suhtract he enters the minuend on the amount keys. He then enters the subtrahend by depressing the keys according to his small numbers (less 1 in the units order) then depresses the 9 keys in all of the hanks to the left which gives the result alcove explain-ed.

The present invention eliminates the neces- .ity for depressing the 9 keys and enables he operator to perform subtraction in a more .asy, more rapid, and a more automatic na The construction for accomplish- 3 this is as follows:

lteierrins' to Figs. 2 to 6, inclusive, it will be observed that an extra series of keys 76 has been provided at the front of the keyboard which, for convenience, will be referred to as column keys as there is one key for each column except the first column on the right for which none is necessary. The keys are mounted in the keyboard so as to be depressible and each is urged upwardly by a spring 71. The lower end of each key stem is slotted to receive a stud 72 on the arm 73 of a yoke 74 pivoted on a shaft 7 5 at the forward end of the machine as illustrated most clearly in F ig. 3, there beinga yoke for each bank except the units hank. The arm 7 8 has a downwardly extending projection 76 to which one end of a spring 77 is connected, the other end being connected to a yoke 91 atthe forward part of the machine. The spring 77 serves to urge its yoke M in a clockwise direction as viewed in Fig; 3. Each of the motor starting bars 36 except the one in the units bank is provided with a downwardly extending projection 7 9 at its forward end which is in the path of the projection 76 on the'arm 73 as shown in Fig. 3. When one of the keys 70 is depressed its yoke 74 is rocked counterclockwise which causes its projection 76 to push its starting bar 86 rearwardly through the medium of the projection 7 9 to start the motor. It will be evident that, whenever one of the keys 70 is depressed, the motor is started and the dll erential mechanism for that bank is connected so as to be driven by the motor, such action taking place automatically upon rearward movement of bar 36 as previously explained.

When themotor is started and the differential mechanism for the bank in question is operated under the conditions above de scribed, it will he appreciated that operation takes place without the depression of any oi the amount t is indexing her for said bank will not be arrested by any of the amount keys. instead the indexing will be moved forward to the limit of its movement which, in this case, corresponds to its 9 position. 9 position of the index,- ing bar is not made dependent upon the position of the cunt keys, hut is determined loy a slot 80 the partition plate for the bank in queen A1115}; bar can ries a stud 82 i s which operates slot stu i l in a slot 80, the OL-Hlg positioned so that when the stud reaches the iorwarc end of the slot. leuicg bar is arrested in its 9 positioii ie result whenever the bar so d, 9 is entered in the register. hezeior he viden e i that when one of the column keys "2 0 is de pressed, the d rential mechanism for said column will be automatically operated and the register pi n corresponding to said column will he moved nine steps.

In order that the differential mechanisms for each of the banks to the left of the d pressed column lrey 70 may be automatically operated to register 9 in the corresponding pinions of the register, the arm 73 oi each of the yokes C 4 except the last one to the left is provided with a relatively long lateral eX- tension 85 which ext-ends to the left and in.

key 70 in Fig. 3 and its yoke 74 is rocked counterclockwise, this rocking action not only causes anaut'omatic operation of. the differential mechanism in mediately to its left so as to cause .an automatic operation of the ban'k'immediately to the left and this action takesplace in sucm cession for all the banks to'the left so that v nism of all the banks to key 70 the mechathe left is automatically operated to enter 9 in the register for all of said banks. This makes it unnecessary to depress the '97? keys. operator merely enters'the complement of upon depression of any the subtrahend and then depresses the column key 70 for the next column to the left whereupon automatic operations take place in all the columns to the left to add the necessary 9s in performing subtraction. This speeds the operation and eliminates the chance of error because only one key need be depressed insteadof a multitude of keys as is necessary when all of the nine keys to the left are depressed. The operation isaudepressed, each of the mechanisms for each bank to the left is automatically connected to be driven to its 9 position.

Interlocking mechanism The machine is provided with an additional feature that preventsthe amount keys in the left hand columns where 9s should be registered from being of the column keys 70 is depressed. Also, means is provided for preventing depression of a column key in one of the columns in which an amount key is being depressed.

' Referring to Fig. '1, it the machine is provided with the familiar pendants 90 between each of the keys of a given bank for preventing more than one key from being depressed at a time. Pivoted at the front of the machine on the shaft 78,

as illustrated in Fig. 3, is a series of arms 91 whose upper ends are adjacent the last of the forward pendants 90 so as to limit the forward movement of the pendants and so as to provide just sufii'cientspace for the lateral projections :92 on the stems of the 1 keys to enter. The forward ends of each of the arms 73 of yokes .74 are provided with lateral projections 93 operating in slots 94 in the' When a column key is depressed, the right handkey in Fig. 93 on .the correspondingarm arms 91. as, for example, 3, the projection :73 cams the arm 91 clockwise to position its j end under the projection 92 on the stem I f I motor 111 response the fact that the pendents90 have no space in which to move and the stems of the other keys cannot enter between them.-

action V cause the rocking of arm its bank, but the lateral extension swings the yoke' 74 1m-' Instead, the

ample, if an depressed while one complement of to. perform subtraction, a register having a calculating 1,key in Fig. 3 is looks the column keys against depression in any column in the space between the arm 91 and'the adjacent pendant 90. Accordingly, if an attempt is made to depress the column key 70 corresponding to said bank, the operator finds the key blocked because clockwise and hence the projection 93 on the arm 7 3 cannot move down and this prevents depression of the column key 70.

Also, when an amount key in any column is depressed, he column keys for the banks of lower'order cannot be depressed. For examount key in a given bank is depressed, the. column key of that bank is locked against depression. This meansthat the arm 73'of said bank cannot beswung the arm 91 cannot move counterclockwise. On account of the overlap ping projections, the column keys of ban of lower orders cannot be depressed unless said arm 7 3 in the first mentioned bank can be swung. Accordingly, the column keys in the banks of lower ordersare locked against depressio' It will be understood that the embodiment of the invention shown is for purposes of illustration only and that variations may be made in it without departing from the spirit and scope of the invention as defined by the appended. claims. will be observed that Iclaim: V 1. A calculator having banks of depressible amount keys upon which the complement of a subtrahend may be entered to perform substractionua registerg calculating mechanism controlled by said keys for operating, sald register in accordance with the value of the keys depressed, and automatic means set lnto operation by manipulation of a single member for automatically perating said register to add ,9 therein in all banks to the left of the last one to the left that is manipulated in the entry of a subtrahend.

2. A motor driven calculator having banksof .depressibleamount keys upon which the. a subtrahend may be entered plurality of pinions, a motor, mechanism operated automatically by said to depression of said amount ke s'to'actuate said registerin accordance w th the value of the keys depressed, and meanscontrolled'by a single manipulative member for causing said motor to auto: matically add 9 in each order of said regisr ter to the left of the last order operated in,

entering a subtra-hend.

3. A motor driven calculator having a plurality of banks of depressible amount keys, an individual calculatin mechanism for each bank operated automatically and individually under the control of and upon depression of the keys of its bank, means controlled by manipulation of a single member for automatically causing operation of the calculating mechanism for a selected bank and all the calculating mechanisms for the banks to the left of it, and means causing said calculating mechanisms, when so operated, to advance the register 9 steps in each of the banks in which a'calculating mechanism is so operated.

4. A motor driven calculator having banks of depressible amount keys, a differential mechanism for each bank, a register operated by said differential mechanisms, a motor, means causing said motor to automatically and individually operate. the differential mechanism for a selected bank in response to depression of a key in said bank, and means controlled by the manipulation of a single member for causing said motor to automatically operate the difierential mechanisms of a selected bank and of all banks to the left of it to add 9 on the register pinions corresponding to the selected bank and all banks to the left of it.

5. A calculator having banks of depressible amount keys, a differential mechanism for each bank, a register operated by said differential v,mechanisms, means automatically and individually operating the differential mechanism of any bank in response to the depression of a key in the selected bank, and column keys each having connections for causing automatic operation of the differential mechanism of its bank and of all banks to the left of it.

6. A calculator having banks of depressible amount keys, a register, a differential mechanism for each bank, means for automatically and individually operating said difierential mechanisms in response to depression of an amount key in a selected bank, column keys, and means operating automatically upon depression of a selected column key to cause the diiferential mechanism of the bank in which the column key is depressed and the differential mechanisms of all banks to the left of it to be automatically operated to add 9 to the register in each of said banks.

motor, column keys for said banks of amount keys, means operated by depression of a selected column key for operating the starting bar for the selected bank, and overlapping connections between said means whereby upon operation of one column key the starting bar operating means for all banks to the left of the depressed column key are operated, and means for indexing in their 9 positions the difierential mechanisms of all the banks that are operated by depression of said column key.

8. A motor driven calculator having banks of depressible amount keys, a differential mechanism for each bank, a register operated by said diiferential mechanisms, a motor, a starting bar for each bank operated by depression of a key of its bank to start the motor and to connect the differential mechanism of its bank to said motor, column keys for said banks having connections for operating the starting bars of their respective banks, and means for indexing in its 9 position the differential mechanism of any bank that is operated by depression of its column key.

9. A motor driven calculator having banks of 'depressible amount keys, a difierential mechanism for each bank controlled by its amount keys, a register operated by said differential mechanisms, a motor, a starting bar for each bank operated by depression of any key of its bank to start the motor and connect the differential mechanism of the selected bank to the motor, a depressible column key' for each bank, a yoke member for each column key arranged to operate the starting bar of its column when the column key is depressed, overlapping connections between said yokes to cause all of the yokes to be operated to the left of the one being operated, and means for indexing in their 9 positions the differential mechanisms in the banks in which yokes are operated through depression of said column key.

10. A calculator having banks of depressible amount keys upon which the complement of a subtrahend may be entered to perform subtraction, a register, a calculating mechanism for each of said banks of keys, each mechanism operating independently when a key in its bank is depressed to actuate the register in accordance with the value of the depressed key, a manipulative member for each bank of amount keys, and means operating when the member in any bank is manipulated to cause the calculating mechanisms in banks to the left of it to add 9 into the register in their respective banks.

In testimony whereof, I have subscribed 

